1. Field of the Invention:
This invention relates to a multi-range load cell weighing scale which ensures a high accuracy of weight determination over a wide weight range.
2. Description of the Prior Art:
There is known a multi-range load cell weighing scale which provides readings in different units depending on the load, as disclosed, for example, in U.S. Pat. No. 4,037,675. For example, there is a weighing scale which can measure a weight of 1 g to 30 kg and indicate each weight in a number of four figures. It is, for example, designed to indicate a weight up to 2.5 kg in a unit of grams and a weight of 2.5 to 30 kg in a unit of 10 grams. More specifically, it indicates a weight of 1.5 kg as 1500 (g) and a weight of 15 kg as 1500 (10 g).
This scale requires load cells which can measure a weight over a wide range of 1 g to 30 kg. There is, however, a specific range only within which each load cell is operative for highly accurate weight determination. A load cell which is operative for highly accurate weight determination over a relatively wide range provides an accurate scale, but is expensive. Even such an expensive load cell has its own limitation and loses its accuracy with a widening in weight range.